Promoting out of stock products

I was contacted by On Air TV on 16/10. I agreed to purchase a new decoder. I was told it would be delivered within 5 days. Now 16 days and several phone calls later, I still have not received the decoder. I have been told that there isn't any stock available and I will have to wait. 48 hours ago I was told I would receive it within 24 hours. When I spoke to a lady this morning she very curtly told me there was nothing she could do about the stock shortage. There was no apology or explanation forthcoming!